Inpatient blood sample rejection: Rates and causes
Vu Dinh PhamObjectives:
To determine the rejection rate of inpatient blood specimens, identify the major causes of specimen rejection, and analyse associated risk factors.
Material and Methods:
A cross-sectional descriptive study was conducted on 30,406 inpatient blood specimens received by the Laboratory Department of Phuc Hung Hospital between January and May 2025. Causes of specimen rejection were classified according to Clinical and Laboratory Standards Institute (CLSI) GP33-A guidelines. Logistic regression analysis was performed to identify factors associated with specimen rejection.
Results:
Of the 30,406 blood specimens analysed, 104 were rejected, corresponding to an overall rejection rate of 0.34%. Rejection rates varied significantly across clinical departments, with the highest rates observed in the Paediatrics Department (1.00%) and the Emergency-Intensive Care Unit-Toxicology Department (0.70%). Haemolysis (25.0%) and patient identification errors (18.3%) were the most common causes of specimen rejection. Compared with the General Internal Medicine Department, the risk of specimen rejection was significantly higher in the Paediatrics Department [odds ratio (OR) = 6.34)], Emergency-Intensive Care Unit-Toxicology Department (OR = 4.57), and Trauma Surgery Department (OR = 2.22).
Conclusion:
Although the overall specimen rejection rate was low, rejection events were concentrated in high-risk departments, particularly Paediatrics and Emergency-Intensive Care Unit-Toxicology. Haemolysis and patient identification errors were the leading causes of specimen rejection. Targeted interventions, including competency-based training in specimen collection, standardised collection procedures, strengthened patient identification practices, and routine monitoring of preanalytical quality indicators, may further reduce specimen rejection rates and improve the reliability of laboratory testing.